Combing Hollow Shell Structure and Z-Scheme Heterojunction Construction for Promoting CO₂ Photoreduction

Abstract

CO2 photoreduction is considered one of the potential ways to achieve carbon neutralization since it uses green solar energy without introducing additional carbon sources during the process of converting CO2 to fuels. However, limited light utilization and poor charge separation often give rise to undesirable CO2 photoreduction performance. Herein, a generic approach using carbon spheres as templates to construct transition metal oxides with multishelled hollow structures is reported. The multishelled hollow structure has been proven to be efficient for improving CO2 photoreduction. Furthermore, we constructed a Z-scheme heterojunction photocatalyst (CdS/Au/ZnCrO4) through introducing CdS into a multishelled hollow ZnCrO4 sphere with Au nanoparticles as a charge transfer medium. Benefiting from the multishelled hollow structure’s induced light utilization and large surface area and Z-scheme heterojuncion promoted charge separation, a high CO production of 2.95 μmol g–1 h–1 was achieved on CdS/Au/ZnCrO4 without using any sacrificial agents, which was 18.4 times and 24.6 times higher than that of CdS and ZnCrO4. This work provides a generic method for constructing controllable multishelled hollow spheres and is expected to offer guidance for promoting CO2 photoreduction through structure regulation and heterojunction construction.

Hollow spherical Ni/ZrO2 as a superior catalyst for syngas production from photothermal synergistic dry reforming of methane

“…This significant improvement can be attributed to the more exposed Ni active site due to a larger specific surface and the multiple reflections caused by the hollow sphere structure. 17 Meanwhile, it is clear that throughout the entire temperature range, the conversion and product yields under PTSC over both catalysts are significantly higher than those under TC conditions. Specifically, under the PTSC conditions and at a temperature of 600 °C, by catalysis of sp-Ni/ZrO 2 , the CH 4 conversion reaches 48.7% (1.2 times higher than the TC conditions), and the CO 2 conversion reaches 55.9% (1.1 times higher than the TC conditions).…”

“…Previous studies have attributed the performance decay of nickel-based catalysts in TC-DRM to metal sintering and carbon deposition. 17 In the case of sp-Ni/ZrO 2 , controlling the ZrO 2 hollow sphere is effective for delaying the migration of nickel particles, 22 suggesting that carbon deposition is the most likely cause of the deterioration in DRM activity. The findings from the carbon balance variation tendencies shown in Fig.…”